Yep, the ThirdParty package carries the 3 big tarballs inside it. The advantage is that it doesn't unpack ~20000 files in a single go... problem is that this is the first time it happens... at least when thinking back to OpenFOAM 1.6?

A quick fix now would be to provide additional instructions in the "unpacking sources" section, such as:

tar xzf OpenFOAM-2.2.0.tgz
tar xzf ThirdParty-2.2.0.tgz

If you choose to do custom builds of OpenFOAM's default ThirdParty packages of Open-MPI and Scotch: